It was the midfielder's first full stint since November in his second reserve outing after recovering from a virus.
Simon scored early to set the wheels in motion of one of our reserves' best performances of the season.
Lee Barnard made it 2-0 before the break and Norwich, lining-up with seven players who have featured in the Premier League this season, including strikers Leon McKenzie and ex-Spur Paul McVeigh, only tested Nicky Eyre from distance once or twice.
On the down side, however, Dean Richards limped off early with a hamstring injury - although his replacement Charlie Lee looked at home again at this level.
It took just four minutes for us to take control as Barnard's cross found the head of Davies who made no mistake.
Our biggest worry on the night arrived after 19 minutes when Phil Mulryne picked out the run of Ryan Jarvis, Eyre dashed out of his area to clear, Jarvis beat him to it and was clattered. Thankfully, the card was only yellow and Mulryne curled the free-kick wide.
Youssef Safri grazed the side-netting 10 minutes later and Eyre was forced into his only flying save by McVeigh in the home side's best spell around the half-hour mark.
But we managed to grab the all-important second goal on 39 minutes. Phil Ifil and David Limbersky worked the ball out of a tight spot on the right touchline, Jamie O'Hara cut in and let fly, Paul Gallacher failed to hold it and Barnard was there to slot home the rebound from six yards - his 10th goal in 12 reserve games this season.
The second half was all Spurs as we dominated possession on a slick surface at Carrow Road. The home side were restricted to two shots from distance, the first 30 minutes into the half, the second in the final minute, both dealt with comfortably by Eyre.
Gallacher was much busier at the other end. He tipped over O'Hara's curling free-kick, beat out a Davies thunderbolt, tipped Barnard's effort wide, somehow kept out Barnard's flick at the near post capped the lot with two brave saves at Barnard's feet just a couple of yards out with five minutes left.
GUIDE TO THE ACTION
4mins: GOAL. Barnard's cross from the right nodded home by Davies.
Norwich 0, Spurs 1
15mins: Injured Richards replaced by Lee.
19mins: Danger as Eyre clattered Jarvis just outside area. Defensive cover there and Eyre showed yellow card. Mulryne curled free-kick just wide.
28mins: Safri free-kick grazed side-netting.
31mins: SAVE. McVeigh 25-yarder forced full-length diving save from Eyre.
34mins: Shackell volleyed Mulryne's corner wide.
39mins: GOAL. Ifil and Limbersky worked ball out of corner to O'Hara, his shot from 20 yards spilled by Gallacher and Barnard there to tap home rebound.
Norwich 0, Spurs 2
44mins: Shackell header and McVeigh volley both blocked in area.
Injury time: Mulryne took quick free-kick, just over, Eyre had it covered though.
Half-time: Norwich 0, Spurs 2
49mins: SAVE. O'Hara free-kick tipped over by Gallacher.
60mins: SAVE. Fine move, Davies wide to Limbersky who cut ball back to Davies on edge of box, drilled first-time effort beat out by Gallacher.
64mins: Barnard 20-yarder tipped wide by Gallacher.
74mins: SAVE. Best move of night, O'Hara wide to Hallfredsson, he played one-two with Davies before whipping in great ball to near post, Barnard there to meet it with flick but Gallacher equal to it.
75mins: Norwich's first shot of half, Blackburn decent hit but straight at Eyre.
85mins: Hallfredsson good ball into Barnard who took ball well but curled wide.
87mins: SAVES. Hallfredsson beat full-back, picked out Barnard only a couple of yards out but acute angle, Gallacher right on top of him and blocked well twice.
Injury time: Another Blackburn effort, carbon copy of earlier shot straight at Eyre from 25 yards.
Full-time: Norwich 0, Spurs 2
Norwich City: Gallacher, Cave-Brown, Brennan, Mulryne, Shackell, Gusterson, Jarvis, Holt (Blackburn, 70), McKenzie (Crow, 51), Safri (Smith. 70), McVeigh. Unused subs: Crow, Howlett.
Spurs: Eyre, Ifil, McKie, Defendi, Richards (Lee, 15), Bunjevcevic, O'Hara, Hallfredsson, Limbersky, Davies, Barnard. Unused subs: Malcolm, Forecast, McKenna, Lewis.
Simon Davies completed 90 minutes and scored as our reserves toppled Norwich City at Carrow Road on Wednesday night.